Australian police say the Solomon Islands rebel leader Harold Keke will be prosecuted for the murder of seven missionaries who were taken hostage in the remote Weathercoast region.

Australia's most senior police officer in the Solomons, Ben McDevitt, said Mr Keke's Guadalcanal Liberation Front was responsible for kidnapping and killing the missionaries.

Mr McDevitt said that although the rebel warlord was not directly involved and was not at the scene of any of the murders, he was the supreme commander of the group that killed them.

The seven hostages were members of an indigenous Anglican order called the Melanesian Brotherhood.

They were held by rebels and at one stage were shown on Australian television smiling and sharing a meal with the rebel leader.

Growing anarchy in the Solomons prompted the sending of an Australian-led multinational intervention force to the islands in July - and the following month, the diplomat in charge of the force said he had learned of the missionaries' deaths.

Mr Keke was one of several gang leaders who surrendered to the intervention force.

Last month he appeared in court in the capital, Honiara, charged with the murder of Father Augustine Geve, a Roman Catholic priest and member of parliament.